For example, Japanese Patent Laid-Open No. 10-131753 discloses a cooling device including a cooling medium circuit in which a cooling medium that is caused to pass through both an engine and a radiator flows, a bypass channel that bypasses the radiator halfway in the cooling medium circuit, and a flow control valve that is provided in the bypass channel. In this device, the flow control valve is configured by a valve housing, and a rotary type rotor that is rotatably installed in the valve housing. By rotating the rotor, opening and closing states of the cooling medium circuit and the bypass channel can be controlled.
Further, Japanese Patent Laid-Open No. 2013-234605 discloses an engine cooling system that causes a cooling medium that passes through the main body of the engine to pass through three cooling medium circuits by an electronic control valve and return to the engine. The system specifically includes a first cooling medium circuit that is provided with a radiator, a second cooling medium circuit that is provided with a heater, and a third cooling medium circuit that is provided with an oil cooler, and the electronic control valve includes three branch valves that open and close the respective cooling medium circuits. In this system, opening degrees of the respective branch valves are controlled independently, and therefore, flow rates of the cooling medium to be caused to flow into the respective cooling medium circuits can be controlled individually.